Combined crystal and bezel ring for dial indicators



April 1969 D. H. ALDEBORGH 3,439,543

COMBINED CRYSTAL AND BEZEL RING FOR DIAL INDICATORS Filed June 23, 1965 INVENTOR. DAVID H. ALDEBORGH ATTORNEYS I United States Patent *Ofice 3,439,543 Patented Apr. 22, 1969 US. Cl. 73-431 3 Claims ABSTRACT OF THE DISCLOSURE An integral bezel-crystal assembly is mounted on a dial indicator housing by expanding the flange portion of the assembly and seating it over an annular rim on the housing. The bezel-crystal assembly may be rotated relative to the housing and retained in an adjusted zero-setting position with the instrument being sealed against the entry of dust therein.

The present invention relates to dial indicators and the like and particularly to a combined crystal and bezel ring for such indicators.

In the past dial indicators have had the face or dial and the cooperating hand thereof protected by a crystal and bezel ordinarily made of two parts, the crystal being either glass or transparent plastic and the bezel of metal.

The structure is usually arranged with a groove on the forward portion of the cylindrical indicator body and a plurality of screws are threaded into the bezel ring and extend into the groove. This arrangement makes it possible to install the bezel-crystal assembly while assuring that it be rotatable in order that a dial element carried by the assembly be rotatable about its center point and thus rotatable with respect to the indicator hand or pointer so that the dial can be set to a zero position.

Additionally the usual assembly has included a clamping member which cooperated with the knurled outer surface of the bezel ring to hold the bezel, crystal and dial assembly in adjusted zero position.

By means of the present invention the construction of the entire bezel ring dial and crystal assembly has been simplified, the bezel ring and crystal being entirely formed of plastic with the face portion transparent and the rim portion opaque.

Additionally the means of mounting the assembly on the dial indicator has likewise been simplified so that no screws are required and a single ring serves to mount the bezel and crystal assembly on the indicator housing While permitting rotation thereof.

It is an object of the invention to provide a one piece crystal and bezel structure for dial indicators and the like.

It is another object of the invention to provide such a one piece structure-in which the entire the structure is made of plastic, the disc-like crystal portion being transparent and the rim portion opaque.

It is another object of the invention to provide such a crystal structure which is readily mounted upon an indicator housing without the aid of any tools and which can be readily removed when necessary.

It is another object of the invention to provide such a crystal-bezel structure and mounting means therefor including means for maintaining the bezel against an annular seat on the housing thus forming a seal preventing entry of dust and foreign materials into the area surrounded by the crystal-bezel structure.

It is a further object of the invention to provide such a crystal assembly and mounting means which enable the bezel ring to be rotated relative to the indicator housing and to be retained in an adjusted position.

Other objects and features of the invention will be apparent when the following description is considered in connection with the annexed drawings, in which,

FIGURE 1 is a perspective exploded view showing a crystal and bezel ring in accordance with my invention together with the dial indicator on which it is mounted and the mode of retaining the bezel ring and other parts in position on the indicator;

FIGURE 2 is an enlarged side elevational view of the gage of FIGURE 1 partially in vertical cross-section showing the bezel ring assembled on the indicator; and

FIGURE 3 is a further enlarged view of the portion of the crystal-bezel and housing shown in section in FIGURE 2.

Referring now to the drawings and particularly to FIGURE 1, there is shown at 10 a dial indicator having the usual cylindrical housing portion 11 with a groove 12 extending circumferentially thereabout adjacent the front thereof. In the usual manner the shaft 13 extends forwardly beyond the housing 11 so that the indicator hand 14- may be mounted thereon.

Adjacent the face element 15 of the housing 11 a spring 16 is provided which bears against the rear surface of the dial 17 when the bezel ring 18 is mounted on the housing. As will be clear particularly from FIGURES 2 and 3, the dial plate 17 seats against a shoulder 20 of the bezel ring 18 being urged into this position by the spring element 16.

Referring now particularly to FIGURES 2 and 3, it will be seen that the face or crystal portion 21 of the ring 18 has a rearwardly extending annular flange 22 which is adapted to extend over the forward portion of the housing 11 as previously described. The disc-like face portion 21 and flange 22 are molded of a clear or transparent plastic material, the flange 22. being provided at its inner surface with the camming rim 23, a recess 24 and the shoulder 20 previously described. The flange 22 is provided on its outer surface with an outwardly projecting rim 25, the forward side of which slopes rearwardly as shown at '29. The flange 22 is also provided with the small shoulder 26 adjacent its forward edge, these two annular projections or rims 25 and 26 serving to fix the opaque rim portion 27 to the flange 22 of the clear plastic. Rim 27 is formed of an opaque plastic material and the flange 22 and crystal 21 are then molded within the flange, the rims 25 and 26 serving to interlock the flange 22 and rim 27.

In addition to the interlocking effect of these projecting rim portions the material of the rim 27 is bonded to that of the flange 22 as the molding operation is performed so that the finished bezel is an integral unit having an opaque rim and a clear face.

As is clear particularly from FIGURES 1 and 3, the outer surface of rim 27 is formed with shallow grooves extending axially giving a knurled effect and making it possible to readily adjust the crystal-bezel ring structure "to a desired rotational position.

A ring 28 of a resilient material and of a cross-sectional diameter to fit in the groove 12 is provided. This ring when in its relaxed condition has a diameter substantially equal to the housing diameter at the base of the groove 12 so that when the ring has been installed in the groove it forms in effect a projection or annular rim on the surface of the housing 12.

The plastic material of which the bezel ring 18 is formed is sufficiently resilient so that it can be installed on the gage housing by placing the rearward edge of the rearwardly flaring camming surface 23 against the ring and then pressing the bezel rearwardly. This results in a momentary flexing of the flange 22 together with the rim 27 until the forward end of the camming surface passes over the ring at which time the flange 22 snaps into the posi- 3 tion shown in FIGURE 3 and retains the bezel ring and crystal unit in position on the gage housing.

It will of course be understood that before installing the bezel ring on the gage, the spring 16 and dial 17 are placed in position with their central openings surrounding the shaft 13 and the pointer 14 positioned on that shaft. Thus as the bezel is installed the outer periphery of the face of the dial bears against the shoulder 20 and the spring 16 is flattened into the shape shown particularly in FIGURE 2.

Spring 16 also serves to maintain a seal between the resilient ring 28 and the seating surface 33 (FIGURE 3), of the flange 22, that is, the spring presses against the dial plate 17 which in turn bears against the shoulder 20 causing the entire bezel assembly to be urged forwardly with surface 33 against the ring 28. The sealing engagement mentioned serves to prevent entry of dust or other foreign matter into the space enclosed by the crystal-bezel assembly and thus assures that dust will not be deposited either on the dial, the crystal or other surfaces such as the pointer 14 or shaft 13. It will be understood that the ring 28 may be a wire ring or a rubber or plastic ring and further that in place of the groove 12 and ring 28 an annular rim may be formed on housing 11.

In addition, the pressure exerted by spring 16 provides adequate friction so that the dial 17 rotates with the bezel when the latter is turned as for adjustment of the zero setting of the gage, there being no appreciable slippage of dial 17 with respect to the shoulder 20.

The cooperation between the wire 28 and the portion 33 of flange 22 not only serves to seal the space within the bezel from the entry of dust or other matter, but also provides a limit to the outer movement of the bezel-crystal structure.

As is usual in gages of the type described, a clamping member 30, FIGURE 1, is provided which cooperates with the knurled surface of the rim 27 and holds the bezel ring 18 and dial 17 in an adjusted position.

As shown in FIGURE 1 this clamping means comprises a screw 31 threaded in the housing 11 and a clamping plate 32 having downwardly extending projections which engage the knurled or serrated surface of rim 27. Customarily the clamping screw 31 extends through an aperture in the plate 32 with the head of the screw bearing against the plate. Also, ordinarily the clamping plate has a downwardly extending lug to the rear of the screw aperture which lug extends into a bore or depression in the gage housing and serves to prevent rotation of the clamping plate about the screw 31.

It will be apparent that the bezel ring, as described above, is advantageous in connection with a dial gage, since it permits of very easy installation on the dial gage requiring no screws to hold it in place while permitting its rotation.

Not only is the bezel ring more easily installed on the What is claimed is:

1. In a dial indicator gage, in combination, a housing of generally cylindrical form, means forming an annular rim about said housing adjacent the forward end thereof, a substantially circular transparent plastic crystal having a rearwardly extending annular flange, a bezel ring of opaque plastic material extending about said crystal flange and being permanently fixed thereto, said combined crystal flange and bezel ring being resilient, said rearwardly extending crystal flange having an annular camming surface at the rear thereof and an elongated recess therein extending forwardly of said carnming surface, a rearward portion of said elongated recess having a shape matching the shape of the adjacent face of said annular rim, said bezel and crystal being mounted on said housing by urging said bezel-crystal structure rearwardly until said camming surface engages said rim and passes thereover, said rim then projecting into said recess, and resilient means urging said bezel and crystal forwardly to maintain said rearward portion of said recess in engagement with said rim to form a seal between said crystal flange and said rim.

2. A dial indicator gage as claimed in claim 1 wherein said means forming said annular rim about said housing comprises an annular groove in said housing and a wire ring seated in said groove and extending upwardly above the surface of said housing.

3. In a dial indicator gage, in combination, a housing of generally cylindrical form, means forming an annular rim about said housing adjacent the forward end thereof, a substantially circular integral crystal and bezel comprising a rearwardly extending resilient flange having an inwardly extending shoulder formed therein to hold an indicator dial, said rearwardly extending flange also having an annular camming surface at the rear thereof and an elongated recess therein extending forwardly of said camming surface, said flange having a forwardly facing annular surface at the rear of said recess matching the rearwardly facing surface of said annular rim, said bezel and crystal being mounted on said housing by urging said bezel-crystal structure rearwardly until said camming surface engages said rim and passes thereover, said rim then seating in said recess, and resilient means comprising a spring between the rearward surface of said indicator dial and the forward face of said housing, said spring urging said bezel and crystal forwardly, to thereby cause the rearward edge of said recess to engage said annular rim to seal the space between said bezel-crystal structure and said housing.

References Cited UNITED STATES PATENTS 2,471,442 5/1949 Morf 73-431 X 2,612,132 9/1952 Triplett 116-114 2,866,940 12/1958 Lamb 73431 X 3,053,094 9/1962 Maugle 73431 3,162,008 12/1964 Berger et al 116129 X 3,209,599 10/1965 Harland et al 73431 3,223,833 12/1965 Protzmann 116129 X 3,226,836 1/1966 Bond 73431 X 3,048,301 8/1962 Arpin 220-82 LOUIS R. PRINCE, Primary Examiner.

D. M. YASICH, Assistant Examiner. 

